The present invention relates to a flush preservation solution to keep cells without a blood supply alive, the use thereof to prevent damage to cells in transplantation, surgery, experimentally and in vitro, a method for preservation, flush or flush preservation, a method for treatment and a kit of parts comprising the solution.
Organ transplantation is now available for kidney, liver, heart, lung, pancreas and intestine. At retrieval a transplant organ is flushed through its vasculature with a preservation solution. This solution is designed to facilitate the reduction of temperature of the organ, prevent cell swelling, remove oxygen free radicals, control pH, reduce ischaemic damage, extend the safe time for which organs can be kept out of the body and facilitate recovery of the organ upon reperfusion.
Important flush solutions were introduced by Belzer in 1967 and Collins in 1969, subsequently modified to Euro-Collins (EC), Marshall (1976), Bretschneider (see Isemer et al 1988), and others. University of Wisconsin solution (UW), the most successful of all solutions, was introduced in 1988 by Belzer and his colleagues. There remains a need for improved flush preservation. Recent evidence indicates that a high quality graft provides both better immediate function and a longer functional graft lifetime.
This area of the literature has been reviewed by: Belzer, 1993; Belzer & Southard, 1988; Bonventre and Weinburg, 1992; Changani et al, 1999; Churchill & Kneteman, 1998; Collins, 1997; Collins & Wicomb, 1992; D'Allesandro et al, 1994; Muhlbacker et al, 1999 and Southard & Belzer, 1995.
A simple flush solution containing only sodium phosphate and sucrose was shown by Andrews and Coffey in 1982, and by Coffey and Andrews in 1983 to protect the morphology of kidney tubules from ischaemic damage. We carried out functional tests and found a similar solution (PBS140) to be highly successful in the preservation of kidney tubules as judged by microperfusion (Pirie and Potts, 1986) when compared to established preservation solutions (EC and Collins C2 solutions). PBS140 was found to provide better preservation of morphology and function of proximal tubules than other solutions. PBS140 was also found to be effective in the preservation of whole kidney function by Ferwana, Pirie and Potts in 1988 and 1989. In experimental transplantation Lam, Mayor, Potts and Giles (1989) found PBS140 to provide highly effective preservation which compared favourably with Hyperosmolar Citrate and UW solution (Lodge, Perry, Skinner, Potts and Giles 1991). PBS140 was tested clinically at Leeds and found to work well for human kidney transplantation (Ahmad, Kashi, Helmy, Hadingham, Potts and Lodge, 1997).
U.S. Pat. No. 4,920,044 describes flush and storage solutions which contain buffers, 20-37 grams per liter mannitol and 0-1.0 grams per liter verapamil. The solutions also contain magnesium and calcium ions, allopurinol and adenosine. The solutions have pH of 7.20-7.50 and osmolality of 255-425 osm/kg. The solutions are used eg. in the transplantation of organs such as kidneys, as flush solutions and further as storage solutions. Examples are shown of 50 hour cold storage with investigation of animal survival, insulin clearance, renal HPLC biopsy, serum creotins and the like in post storage kidney transplants.
U.S. Pat. No. 5,145,771 describes rinse or preservation solutions for organs and tissues for transplant, containing fructose and glucose, nicardipene (calcium blocker), buffer, solutes, allopurinol, glutathione and modified hydroxyethyl starch (colloid). Experiments show 12 hour cold storage of livers with investigation of liver damage (SGOT activity, clotting time, haem, and oxygen fraction) post transplant.
U.S. Pat. No. 5,405,742 describes blood substitute solutions for purging or maintenance of organs during surgery, or for preserving organs for transplantation. The solutions contain solutes, mannitol, buffers, glutathione, an impermeant anion which is lactobionate, iron-chelating agents, calcium channel blockers such as nicardipine and allopurinol. Experiments show three hours cold heart bypass circulation with investigation of serum levels post bypass.
U.S. Pat. No. 5,370,989 describes solutions for organ preservation or maintenance which contain a vasodilator, and also D-glucose, buffers, inorganic ions, and preferably other components such as a calcium blocker, colloids, adenosine etc. Experiments show 24 hours heart preservation with investigation of preservation rating (0-5).
CN-A-1176738 describes solutions for preserving organs for transplantation which contain sugar, a potassium phosphate buffer, the calcium channel blocker verapamil, lactobionate, solutes, a colloid (dextran), allopurinol and reduced glutathione and adenosine.
With the advent of improved immunosuppression came the need for a high performance multi-organ flush solution.
Numerous workers have investigated the development of improved solutions, and in particular of simpler solutions incorporating a number of additives. Efforts have been made to rationalise the results obtained with different formulations. Nevertheless it is apparent that apparently interchangeable additive types may in fact have different effects from those anticipated, this makes formulations extremely specific both in terms of a given type of additive, and in terms of other components present with a given additive since the function is dependent on the formulation as a whole and not simply on an individual constituent. It is moreover apparent that a universal flush solution is a misleading objective, since different organs have quite widely differing requirements. Individual workers have however attempted to focus on essential components which form the basis for flush solutions which may be adapted for specific organs. A number of reviews of the subject are of relevance, in particular “Evaluation of preservation of the intra abdominal organs, F O Belzer, Transplantation Proceedings, vol 25, No 4 (August) 1993, P2527-2530, “Organ Preservation” D'Alessandro et al, Horizons in Organ Transplantation, Vol 74, No. 5, 1994 page 1083-1093, “A comparison of Flushing Solutions for Liver procurement using an isolated perfused Porcine Model”, Bell et al, Aust. N. Z. J. Surg. (1994) 64, 565-568, “New Organ Preservation Solutions”, Collins et al, Kidney International, vol 42, Suppl. 38 (1992) PS197-S202, “Improved Preservation Solutions for Organ Storage”, Changani et al, Transplantation, vol. 68, 345-355, No. 3, 1999 and “Investigation of a Primary Requirement of Organ Preservation Solutions”, Churchill et al, Transplantation, vol. 65, 551-559, No. 4, 1998. Although in part instructive, the individual work and the reviews present so many variables that any meaningful deductions cannot as such be drawn. Design concepts are proposed, such as designing a formulation around essential cellular constituents which are lost or broken down during preservation, and a contrasting concept of designing formulations around constituents which interact with the natural cellular functions and constituents to prevent breakdown, maintain certain functioning or arrest other functioning and the like. The result is that any effective flush solution is likely to be derived by diligent experiment, rather than by deduction or analysis from existing work.
Accordingly there remains a need for a commercially viable and effective flush solution which enables extended preservation of cells in particular of organs and living tissues, including engineered organs and tissues, which provides improved versatility, effectiveness and reperfusion in transplantation, in surgery, including any situation of warm or cold ischaemia, cardioplegia and open heart surgery, whole limb, whole body, or in experimentation.